In simple terms, louvre windows generally consist of a frame containing an operating mechanism in one jamb, a number of louvre blade holding clips, and a number of louvre blades. A louvre window is generally called a “jalousie” in the United States.
The louvre blades are usually rectangular in shape and have two surfaces, longitudinal top and bottom edges and opposed end edges. The blades are typically made of glass but can also be made from timber, plastic, metal and the like. It is known in the art for the longitudinal edges of adjacent blades to overlap each other for weather resistance and security when the window is in the closed state. Typically, a louvre window will have a blade width of 152 mm and a blade pitch of 140 mm, hence having a blade overlap or 12 mm. The known art is illustrated in FIG. 1 with the conventional louvre blade illustrated in FIG. 3.
The opposed end edges of the louvre a blade fit into slots provided in the blade holder clips, which can be made from metal or plastic. When a louvre window is in the closed position, it should be able to prevent wind-driven rain from passing freely between the louvre blades and give protection from forced entry.
When a force is applied to the longitudinal top or bottom edges of the louvre blade, the louvre blade can be dislodged from the blade holder clip and the blade can be removed from the window. This can occur more easily when the window is in the open position and the louvre blade is subject to an impact.
Blade retention typically depends on short L-shaped projections from the blade holder clip at both ends of the slot. To allow the blade to be assembled into the blade holder slot, these projections are typically relatively flexible which in turn limits the resistance force which they can apply against the louvre blade in order to prevent dislodgement of the blade from the blade holder clips.
It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.